1. Field of the Invention
The invention involves the use of a novel microorganism which degrades certain chemical pollutants to non-pollutants under certain appropriate circumstances.
2. Description of the Related Art
U.S. Pat. Nos. 4,863,872 and 5,036,012 disclose a species of the bacterium Pseudomonas (NRRL-B18435) and a process for degrading the toxic organic solvents contained in liquid scintillation fluid in a special apparatus for the biodegradation. These toxic solvents included benzene, toluene, xylene, pseudocumene (1,2,4-trimethylbenzene), dioxane and cyclohexane. The concentration of toxic organic solvents present were from 50-90%. The Pseudomonas culture was capable of degrading the organic solvents when present in concentrations as high as 10,000 ppm. The process of the present invention does not require the use of a special equipment, but rather degrades the chemical pollutants where certain conditions can be met where the pollution occurs.
Appl. Microbiol. Biotechnol., 36, 120 (1991) discloses that a bacterial culture, Rhodococcus, is capable of degradation of dioxane, tetrahydrofuran and other cyclic ethers. However, only limited growth and degradation took place on these cyclic ether substrates.
Russian patent 1,375,646 discloses a bacterium, Xanthomonas, which will degrade THF in drainage water.
Khimiya I Tekhnologiva Vody, 9, 442 (1987) discloses a bacterial culture which grows on a solid medium and which degrade dioxane and THF. However, these cultures are not operable in liquid medium.
The Environmental Protection Agency has listed dioxane as a possible carcinogen in its Fourth Annual Report on Carcinogens (NTP 81-43:131-133, December 1985). Chemical compounds need not be carcinogenic to be considered to be polluting the environment. From time to time dioxane and/or other undesirable chemical pollutants enter the environment. Some of these enter the atmosphere as in Bophal, India while others enter the oceans as the well known oil spill in Valdez, Ak. However, more common are the various industrial chemicals which enter the ground water, streams and lakes as discharge from the many thousands of plants which discharge aqueous waste containing various amounts of toxic chemical pollutants. In the famous case of Diamond v Chakrabarty the claimed microorganism was useful for degrading oil from oil spills. It would be highly desirable to have microorganisms which would degrade other types of toxic chemical pollutants. The present invention involves a microorganism and process for degrading certain toxic chemical pollutants where the pollution occurs.
Non-bacterial fungal microorganisms are known which degrade a variety of environmental pollutants. Russian Patent 1,652,335 discloses a new strain of Streptomyces rochei which will degrade chlofinated phenols and use them for the carbon source. Japanese Patent 62,104,573 discloses removal of tetraalkyl ammonium salts and/or methylated mines from waste water using Nocardia. U.S. Pat. No. 4,505,821 discloses removing phenol and formaldehyde from waste water by treatment with Trichosporon. Japanese Patent 59,046,194 discloses decolofizing lignin sulphonate containing liquid using Penicillium.
The present invention involves the novel non-bacterial microorganism Aureobasidium pullulans identified as NRRL 21064 which by growing to great cell densities efficiently degrades some toxic chemical pollutants in nature where the pollution occurs including at relatively low pH.